Foldable tablet assembly



Nov. 7, 1967 L l.. ANDERSON 3,351,377

FOLDABLE TABLET ASSEMBLY Filed Sept. 26, 1966 l 3 Sheets-SheetI 1 t5)hyd L CHnoLerJom @QT-romsy/ Nov. 7, 1967 L. 1 ANDERSON FOLDABLE TABLETASSEMBLY 5 Sheets-Sheet v2,

A7 WM 7 A.

fig; JVS

Filed Sept. 26, 1966 Nov. 7, 1967 L. ANDERSON FOLDABLE TABLET ASSEMBLY 5ASheets-Shcwt 5 Filed Spc. 26, 1966 United States Patent O 3,351,377FOLDABLE TABLET ASSEMBLY Lloyd L. Anderson, Rockford, lll., assigner toAmerock Corporation, Rockford, Ill., a corporation of Connecticnt FiledSept. 26, 1966, Ser. No. 581,986 11 Claims. (Cl. 297-162) This inventionrelates to a foldable tablet assembly for use with a chair unit such asfound in schools, auditoriums and lecture rooms and, more particularly,to a tablet assembly of the type in which the tablet may be turnedupwardly from la horizontal writing position to a raised positiondisposed at one side of and above the chair seat, swung downwardly andedgewise along the edge of the seat to a lowered position hanging at theside of the seat, and then turned inwardly to a non-obstructive storedposition in which the major portion of the tablet underlies the seat.The tablet travels along the same paths but in opposite directions as itis returned from the stored position to the writing position.

The primary object of the present invention is to lock the tablet formovement along predetermined paths of travel as it is turned and swung`between the various positions and thereby avoid damaging abrasivecontact between the tablet and the stationary elements of the chair unitduring such movement.

A related object is to maintain the tablet spaced from the seat and thearm rest of the chair unit at all times during movement of the tabletbetween its writing and stored positions.

A more detailed object is to provide cooperating guide elements on thetablet and its support to restrict swinging of the tablet while it isbeing turned and to restrict turning of the tablet while it is beingswung.

A Afurther object is to utilize the weight of the tablet for turning thelatter to its stored position automatically as an incident to reachingits lowered position.

Other objects and advantages of the invention will becorne apparent fromthe following detailed description taken in connection with theaccompanying drawings, in which:

FIGURE 1 is a perspective view of a chair unit having a tablet assemblyincorporating the novel features of the present invention.

FIG. 2 is a front elevation of the unit and assembly but showing thetablet in a moved position.

FIG. 3 is a side elevation of the unit and assembly but showing thetablet in another moved position.

FIG. 4 is an enlarged fragmentary side elevation of the tablet assembly.

FIG. 5 is an enlarged fragmentary cross-section taken substantiallyalong the line 5-5 of FIG. 4.

l FIG. 6 is a fragmentary elevational view of parts illustrated in FIG.5 and showing the tablet in a moved position.

FIG. 7 is a fragmentary plan view of parts illustrated in FIG. 6 andshowing the tablet in another moved position.

FIG. 8 is an enlarged fragmentary cross-section taken substantiallyalong the line 8-8 of FIG. 7 and showing the parts n moved positions.

FIG. 9 is an enlarged fragmentary cross-section taken substantiallyalong the line 9-9 of FIG. 4.

As shown in the'drawings for purposes of illustration, the invention isembodied in a foldable tablet assembly installed alongside a chair 1t)of the type especially used in schools and auditoriums. The assemblyincludes a tablet 11 which may be positioned substantially horizontallyas shown in FIG. l to serve as a support for reading and writingmaterials as well as the arm of the user, and

Patented Nov. 7, 1967 which may be folded to an upright stored position(FIG. 3) when not in use to enhance the appearance of the room and toprovide increased seating comfort and aisle space.

In this instance, the chair 10 is of one-piece fiberglass constructionand includes a contoured back rest 12 and a bucket-type seat 13supported on an upright post 14 fastened to the floor of the room.Extending beneath the seat and over the top of the post is a long metalrail 15 of rectangular cross-section mounting a hollow casing 16 forsupporting the tablet 11. The casing is formed by a pair ofsubstantially vertical side plates 17 and 18 which preferably are zinccastings suitably fastened together in laterally spaced relationship todefine yan enclosed interior 19 (FIG. 5). At their lower ends, theplates are formed with U-shaped yokes 20 which fit over and are clampedto the rail. The upper ends of the plates extend parallel to the seatand are shaped to form a horizontal arm rest 21 supporting a cushioningpad 22 (FIG. 5). Usually, a number of chairs are arranged in a rowextending parallel to the rail and each tablet assembly is supported onthe rail adjacent its respective chair.

As shown in FIG. 1, the tablet 11 is formed with a relatively widewriting portion 24 spaced above and overlying the seat 13, and with anarrower neck portion 25 disposed on the arm rest 21 when the tablet isin its horizontal writing position. The tablet is mounted for turning onan arm 27 which, in turn, is fulcrumed on the outer Side plate 17 toswing upwardly and downwardly about a horizont-al axis. To move thetablet to the stored position, it first is turned upwardly relative tothe arm from the writing position to a raised position shown in FIG. 2in which the tablet is disposed at one side of and above the arm restand the scat. The tablet next is swung edgewise and downwardly with thearm 27 to a lowered position hanging by the side of the seat as shown inbroken lines in FIG. 3. Finally, the tablet is turned relative to thearm about an upright axis to the stored position (shown in solid linesin FIG. 3) in which the tablet is generally parallel to the ch-air back12 and the writing portion 24 underlies the seat. In the latterposition, the tablet allows easy entrance to and exit from the chair andalso is disposed advantageously to enable passage of a Hoor-cleaningimplement along the row of chairs. The tablet moves along the same pathsbut in opposite directions as it is returned to the writing position.

More specifically, the arm 27 is made of rugged material such as Zamakand is formed with an inwardly projecting circular hub 30 (FIG. 5)journaled for rotation in an opening formed in the outer side plate 17of the casing 16. A retaining disk 31 disposed within the interior 19 ofthe housing holds the arm on the side plate and is mounted for rotationwith the hub by a series of circumferentially spaced driving lugs 32Iformed integrally with the hub and projecting inwardly through holes inthe disk. The disk and the hub are held together by a retaining ring(not shown) on the inner end of a pin 33 extending through the center ofthe disk and hub.

Flaring gradually upwardly and outwardly from the hub 30 is an armextension 34 (FIG. 5) formed with a hinge boss 35 at its free endrotatably and slidably receiving a cylindrical hinge rod 36. The forwardend of the hinge rod is telescoped into and anchored Within a mountingsleeve 37 fastened to the underside of the tablet 11 by screws. Thus,when the arm 27 is disposed in the upper position shown in FIGS. l and4, the hinge rod 36 is substantially horizontal and the tablet may beturned upwardly about the axis of the rod from. the writing position tothe raised position. As the tablet is swung downwardly to the loweredposition, the arm swings about the axis of the hub 30 to a lowerposition (FIG. 3) in which the hinge rod is disposed vertically so thatthe tablet may be turned inwardly about the hinge rod to the storedposition.

To stabilize the tablet 11 in the writing position, a pair of latchingfmembers 39 and 40 (FIG. 9) on the tablet and the side plate 17,respectively, coact to prevent objectionable sideways motion of thetablet which otherwise might result because of looseness between the hub33 and the side plate. The latching member 39 is a hook formedintegrally with the sleeve 37 and projecting into the latching member 40which herein is simply an eye formed on the upper portion of the sideplate 17 near the arm rest 21. The hook 39 automatically turns into andout of latching engagement with the eye 40 as the tablet is turnedbetween the Writing and raised positions.

Preferably, the tablet 11 is counterbalanced by a pair of contractilesprings 41 (FIGS. 4 and 5) as the arm 27 is swung between the upper andlower positions. The springs are disposed side-by-side within theinterior 19 of the casing 16 and are connected at one end to a yoke 42secured to a crank pin 43 fast on an eccentric extension of theretaining disk 31. At their opposite ends, the springs are anchored to asimilar yoke 44 fastened on an inwardly projecting boss 45 formedintegrally with the side plate 17. Thus, the springs are stretched asthe arm and the tablet are swung downwardly and thereby counterbalancethe weight of these members. In addition, the springs contract as thearm and the tablet are swung upwardly to assist in raising the tabletfrom its lowered position.

In accordance with the primary' aspect of the present invention, thetablet 11 is locked and guided for movement in predetermined pathsspaced from the seat 13 and the arm rest 21 as it is turned and swungbetween the various positions thereby to insure that the tablet will notscrape and scui against the chair elements during such movement. T othis end, the tablet carries a stop or guide element 47 which cooperateswith a guide element 48 on the outer side plate 17 to restrict swingingof the arm 27 while the tablet is being turned about the axis of thehinge rod 36 and also to restrict turning of the tablet while the arm isbeing swung upwardly and downwardly. Accordingly, scratching, scarringand other damage which otherwise would be caused by the tablet and thechair rubbing together are eliminated not only because the tablet mustalways be spaced lfrom the chair before it can be moved between thevarious positions but also because the tablet is positively guided whileit is being moved.

In the present instance, the guide element 47 comprises a substantiallyupright plate fastened to the underside of the neck portion of thetablet 11 by screws 50 extending through a mounting wing 51 (FIGS. 4 and5) integral with and disposed approximately at a right angle to theplate. At its forward end, the guide element is formed with a forwardlyopening eye 52 (FIG. 4) which receives the rear end portion of the hingerod 36. As shown in FIG. 5, the lower edge of the plate is arcuatelycurved about the axis of the hinge rod and is formed with a notch 53which is defined in part by an ear 54 at the lower right hand corner ofthe plate 47.

Herein, the guide element 48 is a laterally projecting rib formedintegrally with the outer side plate 17 of the casing 16 and arcuatelycurved about the axis of the hub 30. The rib curves downwardly andforwardly along the side of the plate 17 from a point adjacent the guideplate 47 when the tablet 11 is in the writing position to a point nearthe front of the casing and level with the axis of the hub. When thetablet is in the writing position and as it is being turned from thewriting position to the raised position, the forward side of the guideIplate 47 engages the upper end 56 of the rib as shown in FIGS. 4 and 5to preventthe arm 27 from swinging downwardly. Then, when the tablet hasbeen turned fully to the raised position. the notch 53 in the guideplate registers with the upper end of the rib (see FIG. 6) to allow thearm and the tablet to swing downwardly. As the tablet is swung towardits lowered position, the ear 54 and the wall of notch opposite the earslide along the rib to guide the tablet and to prevent the latter fromturning about the axis of the hinge rod 36. This insures that the tabletwill not rub and scrape against the arm rest 21 and the chair seat 13during its downward movement. When the tablet reaches its loweredposition and the writing portion 24 is disposed well below the seat, thenotch in the guide plate registers with a notch 57 (FIGS. 4 and 7)formed near the lower end of the rib thus enabling the guide plate toturn through the latter notch and allowing the tablet to be turnedinwardly about the hinge axis to the stored position (FIG. 3).

When the tablet 11 is in the stored position and as it is being turnedoutwardly to the lowered position, the upper face of the guide plate 47engages the top wall of the notch 57 in the rib 48 to prevent the arm 27from swinging upwardly and thus avoiding contact between the writingsurface of the tablet and the lower side of the seat 13. Of course, thetablet may be swung upwardly toward the raised position after it hasbeen turned outwardly sufliciently far to aline the notch 53 in theguide plate with the rib. The rib guides the tablet during its upwardmovement and, after the notch 53 passes the upper end 56 of the rib, thetablet may be turned inwardly and downwardly to its writing position.

In accordance with another aspect of the present invention, the weightof the tablet 11 is utilized to turn the latter to its stored positionautomatically as an incident to reaching the lowered position. For thispurpose, the guide plate 47 is formed with a helical shape and rotateswithin a notch 60 (FIGS. 4 and 8) formed in the extension 34 of the arm27, the notch being located rearwardly of the hinge boss 35. As shownmost clearly in FIG. 8, the edge portion of the downwardly spiralingplate 47 projects into the notch 60 and coacts with the latter somewhatas a screw thread to cam the tablet inwardly about the axis of the hingerod 36 as soon as the tablet reaches its lowered position and thenotches 53 and 57 are alined with each other. The weight of the tabletis sufficient to supply the actuating force for turning the plate 47 inthe notch 60` thus making it unnecessary to turn the tablet manually tothe stored position.

Advantage is taken of this arrangement to aline the notch S3 in theguide plate 47 automatically with the upper end 56 of the guide rib 48as the tablet 11 is raised from the writing position (FIG. 1) to theraised position (FIG. 2). As the tablet is raised, the forward face(FIG. 4) of the helical guide engages the end of the rib and cams thetablet and the hinge rod 36 rearwardly, the hinge rod both rotating andsliding in the hinge boss 35 during such rearward movement. As thetablet is turned upwardly through a sufficient angle to aline the notch53 with the rib, an abutment in the form of a set of jaws 61 (FIGS. 4and 8) formed on the rear end of the sleeve 37 engages and meshes withsimilar set of jaws 62 on the forward end of the stationary boss 35 torestrict further rotation of the arm 27 in a counterclockwise direction(FIG. 2). As a result, the notch 53 cannot be turned beyond the rib andis alined automatically with the latter to allow the tablet to be swungdownwardly to its lowered position.

From the foregoing, it will be apparent that the tablet 11 and the chair10 will retain their original appearance for longer periods of time andWill have a much longer service life than prior arragements of a similarnature since the tablet is always free of contact with the chair duringmovement between the various positions. The guide element 27 not onlylocks and guides the tablet during such movement but also serves as anoperator causing the tablet to turn to its stored positionautomatically. As a result, the tablet assembly is relatively simple inconstruction while being exceptionally maintenance-free in service use.

l claim as my invention:

1. A foldable tablet assembly for use with a chair unit having asubstantially horizontally disposed seat, said assembly having, incombination, a support, an arm fulcrumed on said support for swingingabout a horizontal axis between upper and lower positions, a tablethaving a relatively wide writing portion and a narrower neck portionextending from lsaid writing portion, a pivot member disposed in asubstantially hori- Zontal position when said arm is in said upperposition and mounting said tablet on said arm for 'swinging about asecond substantially horizontal axis transverse to said first axisbetween a substantially horizontal writing position in which aid writingportion overlies the seat and a raised position in which said writingportion is spaced laterally of and above one edge of the seat, saidtablet and said pivot member being movable bodily with said arm as thelatter is swung between said upper and lower positions whereby thetablet is swingable edgewise between said raised position and a loweredposition in which said writing portion is spaced laterally of and belowthe seat, said pivot member being disposed in an upright position whensaid arm is in said lower position and mounting said tablet for turningrelative to said arm between said lowered position and a stored positionin which said writing portion underlies the seat, a guide rib on saidsupport andarcuately curved about said rst axis, a plate having theshape of a helix turnable with said tablet and engageable with said ribto restrict swinging of said arm between said upper and lower positionswhile said tablet is being turned toward and away from said writing andstored positions, said plate having one edge thereof alined with saidrib when said tablet is in said raised and lowered positions to leavesaid arm free for swinging movement between said upper and lowerpositions, said edge overlying and being slidable along and engageablewith said rib while said arm is being swung between said upper and lowerpositions to restrict turning of said tablet relative to said arm and tomaintain the tablet spaced laterally from the one edge of the chair, andmeans on said support coacting with said plate and operable to causesaid tablet to turn from said lowered position to said stored positionautomatically as an incident to said arm reaching said lower position.

2. A tablet assembly as defined in claim 1 in which said plate engagessaid rib to cam said tablet rearwardly relative to said arm as thetablet is turned from said writing position to said raised position, andopposed abutments on said tablet and said arm engageable with each otheras an incident to said rearward movement to restrict turning movement ofthe tablet beyond said raised position and thereby automatically alinesaid one edge of said plate with said rib.

3. A foldable tablet assembly for use with a chair unit having asubstantially horizontally disposed seat, said assembly having, incombination, a support, an arm fulcrumed on said support to swing abouta predetermined axis between upper and lower positions, a tablet havinga writing portion, a pivot member disposed substantially horizontallywhen said arrn is in said upper position and mounting said tablet onsaid arm for turning about an axis transverse to said one axis between asubstantially horizontal Writing position in which said writing portionoverlies the seat and a raised position in which the writing portion isspaced laterally of and above one edge of the seat, said tablet beingmovable bodily with said arm as the latter is swung between said upperand lower positions and being swingable edgewise between said raisedposition and a lowered position in which the writing portion is spacedlaterally of and below the one edge of the seat, a first guide elementon said support and arcuately curved about said one axis, and a secondguide element carried by said tablet and abutting against said rst guideelement as said tablet is turnedl between said writing and raisedpositions to restrict swinging of said arm from said upper to said lowerpositions and sliding along said tirst guide element as said arm isswung between said upper and lower position-s to restrict turning ofsaid tablet relative to the arm and to maintain the tablet spaced fromthe edge of the seat during such swinging.

4. A tablet assembly as defined in claim 3 in which said first guideelement is a rib arcuately curved about said first axis, and said secondguide element comprises a plate turnable with said tablet and abuttingagainst an edge portion of the rib as the tablet is turned between saidwriting and raised positions to restrict swinging of said arm from saidupper to said lower positions, said plate having one edge thereof alinedwith said rib when said tablet is in said raised position, and said edgebeingy slidable along and engageable with said rib as said tablet isswung from said raised position to said lowered position to restrictturning of the tablet relative to the arm.

5. A tablet assembly as defined in claim 3 further including a latchingmember on said tablet engageable with a complementary latching member onthe upper and forward end portion of said support when said tablet is insaid writing position to restrict swinging movement of the tablet aboutan upright axis.

6. A tablet assembly as defined in claim 3 in which said second guideelement comprises a cam turnable with said tabletl and having an edgeportion projecting into a notch formed in said arm for'causing saidtablet to turn from said lowered position to a stored position in whichsaid writing portion underlies the seat automatically as an incident tosaid arm reaching said lower position.

7. A foldable tablet assembly for use with a chair unit having asubstantially horizontally disposed seat, said assembly having, incombination, a support, an arm fu1- crumed on said support to swingabout a horizontal axis between upper and lower positions, a tablethaving a relatively wide writing portion and a narrower neck portionextending from said writing portion, a pivot member disposedsubstantially horizontally when said arm is in said upper position andmounting said tablet on the free end of the ar-m for turning about anaxis transverse to said one axis between a horizontal substantiallyWriting position in which said writing portion overlies the seat and araised position in which the writing portion is spaced laterally of andabove one edge of the seat, said tablet and said pivot member beingmounted for bodily movement with said arm as the latter is swung betweensaid upper and lower positions whereby the tablet is swingable edgewisebetween said raised position and a lowered position in which saidwriting portion is spaced laterally of and below the one edge of theseat, said pivot member being disposed in an upright position when saidarm is in said lower position and mounting said tablet for turningbetween said lowered position and a stored position in which saidwriting portion underlies the seat, and a stop carried by said tabletand engageable with said support to restrict Swingin-g of said armbetween said upper and lower positions while said tablet is being turnedtoward and away from said writing and stored positions and to restrictturning of said tablet relative to said arm while the latter is beingswung between said upper and lower positions.

8. A foldable tablet assembly for use with a chair unit having asubstantially horizontally disposed seat, said assembly having, incombination, a support, an arm fulcrumed on said support to swing abouta horizontal axis between upper and lower positions, a tablet having arelatively wide writing portion and a narrower neck portion extendingfro-m -said writing portion, a pivot member disposed substantiallyhorizontally when said arm is in said upper position and mounting saidtablet on the free end of said arm for turning about a secondsubstantially horizontal axis between a substantially horizontal writingposition in which said writing portion overlies the seat and a raisedposition in which the writing portion is spaced laterally of and aboveone edge of the seat, said tablet and said pivot member being mountedfor bodily movement with said arm as the latter is swung between saidupper and lower positions whereby the tablet is swingable edgewisebetween said raised position and a lowered position in which saidwriting portion is spaced laterally of and below the one edge of theseat, said pivot member being disposed in an upright position when saidarm is in said lower position and mounting said tabletfor turningbetween said lowered position and a stored position in which saidwriting portion underlies the seat, and means carried by said tablet andoperable in conjunction with the wei-ght of the tablet to cam the tabletabout the axis of said pivot ymember and turn the tablet from saidlowered position to said stored position automatically as an incident tothe arm reaching said lower position.

9. A tablet assembly as defined in claim 3 in which said means comprisesa cam element turnable with said tablet and having an edge portionprojecting within a notch formed in said arm.

10. A tablet assembly as defined in claim 9 in which said cam elementhas the shape of a downwardly spiraling helix when said tablet is insaid lowered position.

11. A foldable tablet assembly for use with a chair unit having asubstantially horizontally disposed seat, said assembly having, incombination, a support, an arm fulcrumed on said Isupport to swing abouta first predeter- CII mined axis between upper and lower positions, 'atablet having a writing portion, a pivot member disposed substantiallyhorizontally when said arm is in said upper position and mounting saidtablet on said arm for turning about a second predetermined axis betweena substantially horizontal writing position in which said writingportion overlies the seat and a raised position in which the writin-gportion is spaced laterally of and above one edge of the seat, saidtablet being movable bodily with said arm as the latter is swung betweensaid upper and lower positions and being swingable edgewise between saidraised position and a lowered -position in which the writing lportion isspaced laterally of and below the one edge of the seat, a rst guideelement on said support and arcuately curved about said lirst axis, anda second guide element carried by said tablet and operable to slidealong and enga-ge said rst guide element as said arm is swung betweensaid upper and lower positions to restrict turning of said tabletrelative to the arm and to maintain the tablet spaced from the edge ofthe seat during such sw1ngmg.

References Cited UNITED STATES PATENTS 3,116,093 12/ 1963 Bosack 297-4173,197,253 7/l965 lBrown 297-162 X 3,233,939 2/1966l Chapman 297-1623,269,772 8/1966 Brunskole 297-162 3,292,972 12/1966 Krueger 297-162CASMIR A. NUNBERG, Primary Examiner.

1. A FOLDABLE TABLET ASSEMBLY FOR USE WITH A CHAIR UNIT HAVING ASUBSTANTIALLY HORIZONTALLY DISPOSED SEAT, SAID ASSEMBLY HAVING, INCOMBINATION, A SUPPORT, AN ARM FULCRUMED ON SAID SUPPORT FOR SWINGINGABOUT A HORIZONTAL AXIS BETWEEN UPPER AND LOWER POSITIONS, A TABLETHAVING A RELATIVELY WIDE WRITING PORTION AND A NARROWER NECK PORTIONEXTENDING FROM SAID WRITING PORTION, A PIVOT MEMBER DISPOSED IN ASUBSTANTIALLY HORIZONTAL POSITION WHEN SAID ARM IS IN SAID UPPERPOSITION AND MOUNTING SAID TABLET ON SAID ARM FOR SWINGING ABOUT ASECOND SUBSTANTIALLY HORIZONTAL AXIS TRANSVERSE TO SAID FIRST AXISBETWEEN A SUBSTANTIALLY HORIZONTAL WRITING POSITION IN WHICH AID WRITINGPORTION OVERLIES THE SEAT AND A RAISED POSITION IN WHICH SAID WRITINGPORTION IS SPACED LATERALLY OF AND ABOVE ONE EDGE OF THE SEAT, SAIDTABLET AND SAID PIVOT MEMBER BEING MOVABLE BODILY WITH SAID ARM AS THELATTER IS SWUNG BETWEEN SAID UPPER AND LOWER POSITIONS WHEREBY THETABLET IS SWINGABLE EDGEWISE BETWEEN SAID RAISED POSITION AND A LOWEREDPOSITION IN WHICH SAID WRITING PORTION IS SPACED LATERALLY OF AND BELOWTHE SEAT, SAID PIVOT MEMBER BEING DISPOSED IN AN UPRIGHT POSITION WHENSAID ARM IS IN SAID LOWER POSITION AND MOUNTING SAID TABLET FOR TURNINGRELATIVE TO SAID ARM BETWEEN SAID LOWERED POSITION AND A STORED POSITIONIN WHICH SAID WRITING PORTION UNDERLIES THE SEAT, A GUIDE RIB ON SAIDSUPPORT AND ARCUATELY CURVED ABOUT SAID FIRST AXIS, A PLATE HAVING THESHAPE OF A HELIX TURNABLE WITH SAID TABLET AND ENGAGEABLE WITH SAID RIBTO RESTRICT SWINGING OF SAID ARM BETWEEN SAID UPPER AND LOWER POSITIONSWHILE SAID TABLET IS BEING TURNED TOWARD AND AWAY FROM SAID WRITING ANDSTORED POSITIONS, SAID PLATE HAVING ONE EDGE THEREOF ALINED WITH SAIDRIB WHEN SAID TABLET IS IN SAID RAISED AND LOWERED POSITIONS TO LEAVESAID ARM FREE FOR SWINGING MOVEMENT BETWEEN SAID UPPER AND LOWERPOSITIONS, SAID EDGE OVERLYING AND BEING SLIDABLE ALONG AND ENGAGEABLEWITH SAID RIB WHILE SAID ARM IS BEING SWUNG BETWEEN SAID UPPER AND LOWERPOSITIONS TO RESTRICT TURNING OF SAID TABLET RELATIVE TO SAID ARM AND TOMAINTAIN THE TABLET SPACED LATERALLY FROM THE ONE EDGE OF THE CHAIR, ANDMEANS ON SAID SUPPORT COACTING WITH SAID PLATE AND OPERABLE TO CAUSESAID TABLET TO TURN FROM SAID LOWERED POSITION TO SAID STORED POSITIONAUTOMATICALLY AS AN INCIDENT TO SAID ARM REACHING SAID LOWER POSITION.